Climate instability and tipping points in the Late Devonian: Detection of the Hangenberg Event in an open oceanic island arc in the Central Asian Orogenic Belt

Sedimentary petrology and trace element geochemistry indicate that the Late Devonian to Early Carboniferous Heishantou Formation near Boulongour Reservoir (NW Xinjiang, China) was deposited on a steep slope, mid-latitude accreting island arc complex in an open oceanic system. Bulk 87Sr/86Sr ratios show excursion patterns that are consistent with excursions at the Devonian-Carboniferous (D-C) boundary in epicontinental margin sediments. Sedimentation rates for the Boulongour Reservoir sediments show highly variable rates that range from 0.5 cm/ky to 10 cm/ky, consistent with other Late Devonian sections and modern arc environments. Multiple whole rock geochemical proxies for anoxia and the size and distribution of pyrite framboids suggest the presence of the Hangenberg Event in the sediments associated with the D-C boundary, despite the lack of visible black shale. The presence of anoxia in an open ocean, island arc environment cannot be explained by upwelling of anoxic bottom waters at this paleolatitude, but can be explained by the global infliction of oceanic shallow water eutrophication on to a climate system in distress

On the age of the upper part of La Valute Limestone (Carnic Alps)

4nonenoneCORRADINI C; PONDRELLI M; SUTTNER T.J; SCHNELLB?CHER PCorradini, C; Pondrelli, M; SUTTNER T., J; Schnellb?cher,

Conodonts from Late Devonian island arc settings (Baruunhuurai Terrane, western Mongolia)

Upper Devonian marine deposits of the Baruunhuurai Terrane in western Mongolia represent island arc settings, which yielded a diverse conodont assemblage of 30 taxa, including species of Ancyrognathus (as well as one new species), Icriodus, Mehlina, Polygnathus and Palmatolepis. Biodiversity analysis of Ancyrognathus, Pelekysgnathus, Mehlina and Icriodus shows that the Mongolian conodont assemblage consists of two endemic and few cosmopolitan taxa. Representatives of the otherwise globally distributed genus Pelekysgnathus are absent. An important factor influencing the regional distribution of conodont taxa seems to be the siliciclastic-dominated sedimentation of the Baruunhuurai Terrane during the early Famennian

The age of the La Valute limestone-Findenig limestone transition in the La Valute Section (Lower Devonian, Carnic Alps, Italy)

The Lower Devonian sequence at La Valute cave is about 8 meters thick and includes the boundary of La Volute limestone and Findenig limestone. It is represented by pelagic deposits yielding dacryoconarids, nautiloids, ostracods, trilobites, brachiopods, some crinoid stem-plates and conodonts. In order to give an age constrain for the formation-boundary fifteen conodont samples were collected and processed. Apart from some barren samples, a quite diverse Lochkovian fauna is obtained. Conodont genera like Ancyrodelloides, Belodella, Dvorakia, Flajsella, Lanea, Oulodus, Pedavis, Pseudooneotodus, Wurmiella and Zieglerodina have been identified. Distinctive conodont-assemblages belong to two middle-late Lochkovian biozones, the trigonicus Zone (upper part of La Valute limestone) and the pandora beta Zone (base of Findenig limestone), which allow the allocation of the formation-boundary near the base of the pandora beta Zone

Middle Devonian rugose corals of the Carnic Alps ans their relation to tha Late Eifelian Kacak Event

7nonenoneKIDO E; SUTTNER T.J; PONDRELLI M; CORRADINI C; CORRIGA M.G; SIMONETTO L; BERKYOV? SKido, E; SUTTNER T., J; Pondrelli, M; Corradini, C; CORRIGA M., G; Simonetto, L; Berkyov?,

Correlation of Mid-Devonian coral deposits of the Carnic Alps across the Austro-Italian border.

7nonenoneKIDO E.; SUTTNER T.J.; PONDRELLI M.; CORRADINI C; CORRIGA M.G.; SIMONETTO L.; BERKYOV? S.Kido, E.; Suttner, T. J.; Pondrelli, M.; Corradini, C; Corriga, M. G.; Simonetto, L.; Berkyov?, S

Kellergrat Formation

Massive gray limestone with abundant bioclasts and biogenes or reef-building organisms. Largest biogenes are stromatoporoid colonies and tabulate and colonial rugose corals. Amphipora and Stachyodes are common accessory reef builders